Download The Endocrine System – Chapter 9 Notes Second messenger

The Endocrine System – Chapter 9 Notes
Second messenger system of the body
Uses chemical messages (___________________) that are released into the ________________
Hormones control several major processes:
 _________________________
 _____________________________________
 _______________________________________
 _________________________________________________________
 _______________________________
Hormone Overview
 Hormones are produced by special cells
 Cells ______________ hormones into extracellular fluids
 Blood transfers hormones to target sites
 These hormones regulate the activity of other cells
The Chemistry of Hormones
 ________________-Based Hormones
Proteins, Peptides, and Amines
 _________________ - made from cholesterol
 ___________________ - made from highly active lipids
Mechanisms of Hormone Action
 Hormones affect only certain tissues or organs (_______________ cells or organs)
 Target cells must have specific protein _____________________
 Hormone binding influences the workings of the cells
Effects caused by Hormones
Typically, one or more of the following occurs:
 Changes in plasma membrane _____________________ or electrical state
 Synthesis of ___________________, such as enzymes
 Activation or inactivation of _______________________
 Stimulation of _____________________
Steroid Hormone Action
1. ______________ through the plasma membrane of target cells
2. Enter the _____________
3. Bind to a specific ____________ within the nucleus
4. Bind to specific sites on the cell’s ________
5. Activate _________ that result in synthesis of new _________________
Non-Steroid Hormone Action
1. Hormone binds to a membrane _________________
2. Hormone does _________ enter the cell
3. Sets off a series of reactions that activates an _____________
4. Catalyzes a reaction that produces a ____________ _____________ molecule
5. Oversees additional intracellular changes to promote a specific response
Control of Hormone Release
Hormone levels in the blood are maintained by ______________ feedback
A stimulus or low hormone levels in the blood triggers the release of more ________________
Hormone release ___________ once an appropriate level in the blood is reached
Hormonal Stimuli of Endocrine Glands (Fig 9.2a)
Endocrine glands are activated by other ________________
Humoral Stimuli of Endocrine Glands (Fig 9.2b)
Changing ___________ levels of certain ions stimulate hormone release
Neural Stimuli of Endocrine Glands (Fig 9.2c)
__________ _____________ stimulate hormone release (most under control of sympathetic nervous system)
Location of Major Endocrine Organs (Fig 9.3 & handout)
Pituitary Gland
 Size of a grape
 Hangs by a stalk from the hypothalamus
 Protected by the sphenoid bone
 Has two functional lobes:
 Anterior pituitary – glandular tissue
 Posterior pituitary – nervous tissue
Hormones of the Anterior Pituitary (Fig 9.4)
 ______ anterior pituitary hormones
 Two affect non-endocrine targets
 Four stimulate other endocrine glands ( ___________ hormones)
 Characteristic of all anterior pituitary hormones
 Proteins (or peptides)
 Act through second messenger systems
 Regulated by hormonal stimuli; mostly negative feedback
Growth Hormone (GH)
 General metabolic hormone
 Major effects are directed to growth of _______________ muscles and long ____________
 Causes amino acids to be built into proteins
 Causes fats to be broken down for a source of energy
Function of Other Anterior Pituitary Hormones
 _________________ (PRL)
 Stimulates and maintains milk production following childbirth
 Function in males is not well understood
 _______________________ hormone (ACTH)
 Regulates endocrine activity of the adrenal cortex
 _________________________ hormone (TSH or TH)
 Influences growth and activity of the thyroid
 Gonadotrophic hormones:
 Regulate hormonal activity of gonads
 _________________________ hormone (FSH)
 Stimulates follicle development in ovaries
 Stimulates sperm development in testes
 ________________________ hormone (LH)
 Triggers ovulation
 Causes ruptured follicle to become the corpus luteum
 Stimulates testosterone production in men
 In men, referred to as interstitial cell-stimulated hormone (ICSH)
Pituitary-Hypothalamus Relationship
 Release of hormones is controlled by releasing and inhibiting hormones produced by the
_________________
 Hypothalamus produces two hormones that are transported to neurosecretory cells of the __________
pituitary
 The posterior pituitary is not strictly an endocrine gland, but does release hormones
Hormones of the Posterior Pituitary (via Hypothalamus)
 __________________
 Stimulates contractions of the uterus during labor
 Causes milk ejection
 Under positive feedback control
 ______________________ hormone (ADH)


Can inhibit urine production
In large amounts, causes vasoconstriction leading to increased blood pressure (ADH sometimes
called vasopressin)
Thyroid Gland
 Found at the base of the ____________
 Consists of two lobes and a connecting isthmus
 Produces two hormones:
 _____________ hormone
 Major metabolic hormone
 Composed of two active __________-containing hormones
 Thyroxine (T4) – secreted by thyroid follicles
 Triiodothyroxine (T3) – conversion of T4 at target tissues
 _______________ – enlargement of the thyroid gland due to iodine deficiency
 ____________’ disease – one form of hyperthyroidism; causes high basal metabolic
rate, intolerance of heat, rapid heartbeat, weight loss, inability to relax, bulging eyes
 ________________ (Fig 9.9)
 _____________ blood ____________ levels by causing its deposition on bone
 Antagonistic to ___________________ hormone
 Produced by C (parafollicular) cells
Parathyroid Glands
 Tiny masses on the posterior of thyroid
 Secrete parathyroid hormone
 Stimulate osteoclasts to remove calcium from bone
 Stimulate the kidneys and intestine to absorb more calcium
 ____________ _______________ levels in the blood
Adrenal Glands
 Two glands:
 __________ – outer glandular region in three layers
 __________ – inner neural tissue region
 Sits on top of the ________________
Hormones of the Adrenal Cortex (Fig 9.10)
 Mineralocorticoids (mainly ______________________)
 Produced in outer adrenal cortex
 Regulate mineral content in blood; also water, and electrolyte balance
 Target organ is the ________________
 Production stimulated by renin (enzyme in kidney)
 Aldosterone production inhibited by atrial natriuretic peptide (hormone released by heart)
 Glucocorticoids (including _______________ and ____________________)
 Produced in the middle layer of the adrenal cortex
 Promote normal cell metabolism
 Help resist long-term stressors by increasing blood glucose levels
 Decrease edema and inhibit pain-causing prostaglandins
 Released in response to increased levels of ACTH
___________’s disease – excessive output of glucocorticoids results in characteristic “buffalo hump”
 Sex hormones
 Produced in the inner layer of the adrenal cortex
 Androgens (male) and some estrogen (female)
Hormones of the Adrenal Medulla (Fig 9.12)
 Produce two similar hormones (catecholamines) to deal with short-term stress
 Epinepherine
 Norepinepherine
Pancreatic Islets (Fig 9.14)
 The pancreas is a mixed gland
 The islets of the pancreas produce hormones
 ____________ – allows glucose to cross plasma membranes into cells from beta cells
 ____________ - allows glucose to enter the blood from alpha cells
 These hormones are antagonists that maintain ____________ __________ homeostasis
Pineal Gland
 Found on the third ventricle of the brain
 Secretes ________________
 Helps establish the body’s wake and sleep cycles
 May have other functions
Thymus Gland
 Located posterior to the ________________
 Largest in infants and children
 Produces __________________
 Matures some types of white blood cells (T cells)
 Important in developing the immune system
Hormones of the Ovaries
 _________________
 Produced by _____________ follicles or the placenta
 Stimulates the development of secondary female characteristics
 Matures female reproductive organs
 Helps prepare the uterus to receive a fertilized egg
 Helps maintain _____________________
 Prepares the breasts to produce milk
 ____________________
 Produced by the ___________ ______________
 Acts with estrogen to bring about the menstrual cycle
 Helps in the implantation of an embryo in the uterus
Hormones of the Testes
 _______________ cells of testes are hormone-producing
 Produce several androgens
 ____________________ is the most important androgen
 Responsible from adult male secondary sex characteristics
 Promotes growth and maturation of male reproductive system
 Required for sperm cell production
Other Hormone-Producing Tissues and Organs
 Parts of the __________ _________________
 Parts of the ______________
 Parts of the _________________
 Parts of the ________________
 Many other areas have scattered endocrine cells
Endocrine Function of the Placenta
 Produces hormones that maintain __________________
 Some hormones play a part in the __________________ of the baby
 Produces _________ in addition to estrogen, progesterone, and other hormones
Developmental Aspects of the Endocrine System
 Most endocrine organs operate smoothly until old age
 ______________ is brought about by lack of efficiency of the ovaries
 Problems associated with reduced estrogen are common
 Growth hormone production declines with age